1. Field of the Invention
The invention relates to rotary blade systems for pulverizing hard and compacted surfaces such as in rototilling to prepare ground for planting.
2. Description of the Prior Art
Manual methods, such as a shoveling, are often not sufficient to break up or pulverize compacted and hard surfaces. In addition to requiring extensive time and physical effort, manual methods are rarely capable of fully pulverizing the compacted surface. For this reason, mechanized tools and implements are often used to pulverize or break up compacted or hard surfaces.
There are many existing examples of mechanical tillers and the like. For example, U.S. Pat. No. 2,943,687 to Merry et al. for a Reversible Earth Working Tiller; U.S. Pat. No. 4,062,408 to Enters et al. for a Rotary Tiller Tine Assembly; U.S. Pat. No. 4,002,205 to Falk for a Horticultural Device; U.S. Pat. No. 3,658,135 to Thompson for a Rotary Tiller With Backup Plate Furrowing Means; U.S. Pat. No. 3,362,482 to Riddle for a Rotor For Ground Working Equipment; U.S. Pat. No. 1,635,612 to Dick et al. for an Agricultural Machine; U.S. Pat. No. 1,684,861 to Dirschauer for an Agricultural Machine; U.S. Pat. No. 5,048,616 to Hoff for a Garden Tiller Tine Assembly; U.S. Pat. No. 4,372,397 to Goertzen et al. for a Garden Tiller With Extended Tine Shield; and U.S. Pat. No. 4,278,133 to de Marcellus for Attachments For Lawn Edgers all show mechanized tools for earth working. While all these tools employ a rotary action, they all consist of cutting blades that primarily lie in a vertical plane relative to the surface to be worked, some additionally having flanges extending from the distal end of the cutting blades substantially parallel to the axis of rotation.
The orientation of these blades gives rise to two problems. First, when the vertically oriented rotating blades strike the compacted surface the apparatus is forced upward, away from the surface to be worked. It requires a great deal of effort, strength and control to overcome this force and to keep the cutting blades in contact with the compacted surface while moving the apparatus forward. Secondly, the generally vertical faces of the cutting blades cause the substance to be essentially shoveled quickly to the rear of the apparatus. This does not permit the surface to be fully pulverized; rather, it tends to create large chunks of still-compacted material.
The gardening hobbyist creates special requirements for such mechanized tillers. The industrial work place assumes the operator will possess sufficient strength to wrestle with equipment as required to achieve the desired function. The backyard gardener, however, is often not able to force a heavy piece of equipment as desired, due to a lack of strength or technique. Often soil tilling equipment is rented on a seasonal basis as needed to prepare the soil. The operator spends little time learning how to most effectively operate the equipment and ends up learning by doing--starting up the equipment and beginning the task. This often results in a frustrated operator, and presents a significant safety risk.
The blades of a conventional tiller are difficult to maintain and replace. Tilling blades, or tines, of conventional design impact the soil in succession, resulting in a lurching or bouncing motion, which is hard on the operator and the equipment. Tilling dulls and often bends tilling blades due to the nature of the blades rotational impacting of the soil surface and buried objects often contained in soils, such as rocks, tree roots and clays. The gardening hobbyist is especially discouraged when confronted by a damaged blade. Repairing a blade typically requires skills and tools the gardening hobbyist does not possess, thus requiring either taking the equipment to a repair shop or expensive on-site repair.
In light of the above, a need exists for an apparatus for breaking up hard surfaces, as found in soil tilling, which is superior to conventional means in that it pulls into the surface to be tilled as it rotates rather than requiring the operator or machinery to push the rotating tilling mechanism down and into the surface, allowing for complete pulverization of the material.
A further need exists for a rotary blade system employed in a tiller which is maintained and replaced in a simple manner.